Method of producing colored smoke clouds



eirsaoz OR STATES PATENT OFFICE.

JOHN CLIFFORD SAVAGE, OF NEW YORK, N. Y.

METHOD OF PRODUCING No Drawing. Application filed April 3,

This invention relates to the formation of colored smoke for signalling,advertising, smoke screen or other work, and has particular but notexclusive reference to the forn ing of clouds or trails of colored smokefrom aircraft.

My invention comprises a new method of producing colored smoke, and inone phase thereof provides a smoke producing mixture or mixtures whichmay be non-inflammable or non-toxic.

Heretofore, mixtures for the production of colored smoke have dependedfor their ability to function on the inclusion in their composition ofcertain chemicals which react with sufficient heat to insurevaporization of the coloring medium, and usually there is actualcombustion of one or more of the ingredients for the generation of heat.

In my method the heat necessary to vaporize the compound is providedfrom external and not from internal sources and the compound employed byme does not necessarily include among its constituents material ormaterials, such as lactose and potassium chlorate, which are expresslyincluded in the usual compound to provide a heat producing reaction.

I have discovered that all systems of colored smoke production dependingupon combustion of one or more ingredients lose in efficiency, for thereason that in every case a certain proportion of the coloring medium isburnt, with consequently a very considerable loss in color value.

The aim of my invention is to prevent any part of the coloring mediumbeing combusted and I therefore employ a mixture, the

pgnstituentsoi which danot react in the COLORED SMOKE cLoU ns.

1924. Serial No. 704,081.

ample of my colored smoke producing mixture is as follows Orange oilsoluble aniline dye 10 pounds.

Light mineral lubricating oil 1 gallon. Tetrachlorethane or carbontetrachloride 1 pint.

This mixture, when introduced into the exhaust of a gasoline engine, isvaporized and, when ejected into the air, condenses to form a red smoke.In practice I have run a pipe from the exhaust manifold of an aeroplaneto the rear of the fuselage and have fed the smoke producing mixtureinto said pipe at a point approximately four feet from the manifold. Thecoloring agent is the aniline dye, and the mineral oil acts as a vehicleand a base smoke, which base smoke is colored by the exceedingly fineparticles of the condensed coloring material.

WVhile my invention finds its most ready application in connection withthe exhaust of an internal combustion engine, its method of operation isnot limited to this. I may for example, employ a stream of steam,superheated if necessary, and directly or indirectly into contact withmy compound, to provide sufficient heat to effect the necessaryvaporization thereof or any other method, the essential factor beingthat no (or a negligible amount of) combustion shall take place and thatthe hot gases or vapors shall be sufficient temperature to effect therequisite vaporization.

Although one phase of my invention aims at the prevention of wastage ofcoloring ma terial by completely avoiding combustion, I am aware that incases where my type of mixture is introduced into the exhaust gases of agasoline motor, and in cases where such motor is running on animperfectly carbureted mixture, there may be some free oxygen, carbonmonoxide or other combustion supportlng material present in the exhaustgases and consequently some degree of c0mbustion, but such accidentaloccurrences do not upset the principle of my invention.

To produce a green smoke I employ a mixture of orange oil solubleaniline dye and synthetic indigo blended in suitable proportions tosecure the requisite shade of green, the other ingredients remaining thesame. Black or dark-grey smokes can be secured by the inclusion ofanthracene in the mixture in place of the aniline, or purple smokes bythe inclusion of iodine.

In the attached claims by primary/secondary coloration medium I mean acoloration medium producing one of the primary colors of the spectrum,or a shade, to wit a secondary color, as for example purple.

Having described my invention what I claim and desire to secure byLetters Patent is as follows':-

1. The method of producing colored smoke clouds or trails, whichconsists in vaporizing a primary/secondary coloration medium in theabsence of combustion and producing a base smoke neutral thereto, andejecting the two in conjunction into the atmosphere.

. 2. The method of producing colored smoke clouds or trails, whichconsists in vaporizing a material which, when condensed, forms a whitesmoke, and coloring the base smoke by mixing the same wlth aprimary/secondary coloration medium in the absence of combustion. V

3. The method of producing primary/ secondary colored smoke clouds ortrails, which consists in vaporizing a material which, when condensed,forms a white smoke, vaporizing a primary/secondary coloration medium inthe absence of combustion and coloring the base smoke by condensation ofthe coloration medium vapor.

4. The method of producing primary/secondary colored smoke clouds ortrails which consists in subjecting oil and a vaporizable colorationmedium to heat whereby the said substances are conjointly vaporized, andejecting the vapors thus formed into the atmosphere.

5. The method of producing primary/secondary colored smoke clouds ortrails which consists in mixing oil and a vaporizable coloration mediumto form a body which will flow, flowing said body into a chambersubjected to heat wherein the body is vaporized, and ejecting the vaporinto the atmosphere.

6. The method of producing primary/ secondary colored smoke clouds ortrails, which consists in vaporizing an oil by sub- "jecting the same toheat, vaporizing a primary/secondary coloration medium, andsimultaneously ejecting the said vapors into the atmosphere.

In testimony whereof, I have signed my name to this specification.

JOHN C. SAVAGE

